Apparatus for automating packaging machines and packaging production lines



Dec. 24, 1968 G. F, WEDL ETAL 3,417,541

APPARATUS FCR AUTCMATING PACKAGING MACHINES AND PACKAGING PRODUCTIONLINES Filed MarCh 5, 1966 5 Sheets-Sheet l .diro/P41515' .mw IO M u H@ CA Ill.

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G. F. WEDL ETAL APPARATUS FOR AUTOMATING PACKAGING MACHINES Dec. 24,1968 AND PACKAGING PRODUCTION LINES 5 Sheets-Sheet 2 Filed March 5. 1966eg'ff' I N VEN TORS L, p f W F w m fa De- 24, 1968 G. F. wenn. ETALAPPARATUS FOR AUTOMATING PACKAGING MACHINES AND PACKAGING PRODUCTIONLINES 3 Sheets-Sheet 5 Filed March 5, 1966 IIIllu-hn.

S. R m@ WW. 1F M a Fig 7 United States Patent O 3,417,541 APPARATUS FORAUTOMATING PACKAGING MACHINES AND PACKAGING PRODUCTION LINES Gerald F.Wedl, Coon Rapids, and Darwin D. Draisey, Minneapolis, Minn., assignorsto Grain Belt Breweries, Inc., a corporation of Minnesota Filed Mar. 3,1966, Ser. No. 531,572 7 Claims. (Cl. 53-55) ABSTRACT OF THE DISCLOSUREA beer can packaging apparatus sensing a shortage of beer cans to stopthe flow of cartons, and sensing a shortage of cartons to stop the ilowof beer cans.

Of the available packaging machines presently on the market,particularly those machines designed to package groups of six cans intoa wrap around carton, none have provided for completely automating themachine by coordinating the packaging machine with the packagingproduction line in such a way that the machine responds to shortages inthe packaging line and the packaging line responds to shortages ofcarton blanks in the packaging machine. Further, presently availablepackaging machines do not consider the packaged product after it leavesthe packaging machine but while it is still in the over-all packagingproduction line, for example enroute to a master packer station.

An example of such a packaging machine may be found in U.S. Patent No.2,986,857, issued June 6, 1961 to Henry Ganz and assigned to theContinental Can Co. Inc., New York, N Y. The Ganz packaging machinewraps a carton blank around a predetermined number of cans, typicallysix cans arranged in two, side by side rows of 3 cans each. No provisionis made for providing a machine responsive to the production line nor isthe production line responsive to the packaging machine. Further, thepackaging machine should dispense carton blanks with the discharge ofgroups of six cans from the production line in such a way that thecarton blank is properly positioned over the cans at the point ofwrapping. Oftentimes, the lack of synchronization between the cartonblanks and the production line, which typically follows the dispensingof a faulty carton blank or no blank at all, results in a blank beingdisposed over two or four cans for Wrapping. When this occurs theoperator must shut the machine down and manually insert or exclude theproper number of cans and manually synchronize the carton with the cansand the can discharge. This procedure results in a high percentage ofdowntime and, consequently, results in high packaging cost per packagedunit.

With these comments in mind it is to the elimination of these and otherdisadvantages to which the present invention is directed along with theinclusion therein of other novel and desirable features.

An object of our invention is to provide a new and improved method andapparatus for automating packaging production lines of simple andinexpensive construction and operation.

Another object of our invention is the provision of a packaging machinewhich responds to the packaging production line and includes means tocontrol the production line in response to the machine.

Another object of our invention is the provision of a packagingproduction line which responds to the packaging machine and includesmeans to control the packaging machine in response to the productionline.

Still another object of our invention is the provision rice l of amethod and apparatus for controlling the ow of units to be packaged inresponse to the packaging medium and simultaneously controlling the flowof the packaging medium in response to the units to be packaged.

Another object of our invention is the provision of apparatus fordispensing the packaging medium at a predetermined time as Well asinterrupting the flow of packaging medium at a predetermined time inresponse to the units to be packaged.

Another object of our invention is the provision of apparatus to indexthe units to be packed into groups of predetermined numbers as well asto control the ow of a predetermined number of units in response to thepackaging medium.

A still further object of our invention is the provision of an automatedpackaging machine and package production line eliminating the need for ahighly skilled operator and requiring only an operator of minimum skillor manual dexterity.

These and other objects and advantages of our invention will more fullyappear from the following description made in connection with theaccompanying drawings wherein like reference characters refer to thesame or similar parts throughout the several views, and in which:

FIG. l is a side elevation showing a packaging machine with incomingcans from the production line and the outgoing packaged product; theproduction lines and machine shown complete with the apparatus of myinvention for automating the packaging of the product.

FIG. 2 is an enlarged partial perspective view showing the carton blankdispensing mechanism and synchronization assembly.

FIG. 3 is an enlarged partial plan view showing the can indexing andspacing assembly.

FIG. 4 is an enlarged partial perspective view showing the carton blanksensing limit switches and a carton blank.

FIG. 5 is an enlarged partial plan view showing the production linepressure gate and can sensing assembly.

FIG. 6 is an enlarged partial cross-sectional View taken along the line6 6 of FIG. 2 and showing the carton dispensing assembly.

FIG. 7 is an enlarged partial side elevation showing the pressure gateassembly and the auxiliary sensing assembly in the production line.

One form of the present invention is shown in the drawings and isdescribed herein. The packaging machine is shown in FIG. l, indicated ingeneral by numeral 10. The machine includes suitable supportingstructure 10a. A start-stop switch is indicated at 10b and a cartonblank dispensing override switch at 10c. The override is utilized toclean-out the machine at the end 0f the day. The machine and productionline are each connected to a suitable power source (not shown). Theincoming production line and supporting structure is indicated at 11,and the outgoing production line of packaged products is indicated at12. Cans 13 are shown on the incoming production line and packaged cans14 are shown on the outgoing production line 12. Direction of flow ofthe cans is from the right to the left in FIG. l as indicated by thearrow. As cans 13 proceed from the production line 11 into the wrappingstation of machine 1G, carton blanks are dispensed by the cartondispensing assembly, indicated in general by numeral 15. Individualcarton blanks are dispensed for oW through the machine 10 to thewrapping station at intervals synchronized with the ow of groups of cansthrough the machine so that a blank and corresponding cans arrive at thewrapping station at the same time. The cans are indexed in groups of sixand are Wrapped by machine 10 in any of several conventional ways. Onemanner of wrapping cans is clearly disclosed in the above mentioned 3Ganz patent. Further explanation of the wrapping apparatus and processis deemed unnecessary except as it relates to our invention.

FIG. 1 shows the carton dispensing assembly 15 which includes a hopper16 for containing the carton blanks and a bottom opening 17 fordispensing the carton blanks 18. A series of suction cups 19 aredisposed transversely of the direction of travel of the cans andunderneath opening 17 of hopper 16. Suction cups 19 are energized bypneumatic valve 20. The hopper 16 is attached to machine 1t) withbracket 21 and valve 2t) is attached to the machine supportingstructure, and connected to suction cups 19 through hose 21a. Suction`cups 19 are actuated upwardly to engage the lowermost carton blank inhopper 16 and, with the suction at each of the cups, draw off the bottomcarton blank, and feed it into rollers which are shown in FIG. 6. Themechanical apparatus for alternately raising and lowering suction cups19 is not shown, but may be done in any of several conventional ways.Suction cups 19 are synchronized with cans 12 in such a way that acarton is dispensed each time .a group of six cans enters the machine.Further, if cans are not in the incoming production line the cartonblank is not released. The carton blank is fed onto conveying chains 22which in turn feed the carton blank onto conveying chains 23. The cartonblank 18 rests on these chains and is carried thereon to the cans to bepacked. Limit switches 24 have sensors 24a attached thereto whichmaintain contact with the dispensed carton and, in the instance ofinterrupted ow of carton blanks, provide electrical signal means forinterrupting the flow of cans until such time as the next carton isdispensed. Frequently the iiow of cartons is interrupted when thesuction cups 19 fail to draw off a carton blank due to, for example,blanks adhering together from moist conditions, faulty ink or othermalfunctions.

The can indexing assembly is indicated at numeral 25, in FIG. 1, and isshown in plan view in FIG. 3. The cans are indexed into groups of six,three in each of two rows. Referring to FIG. 3, the can conveyor isindicated at 26 and is of conventional construction. The conveyor movesas indicated by the arrow in FIG. 3, conveying the cans toward canindexing assembly 25. A divider 27 separates the cans into two rows. Themachine housing is indicated at 28 and supporting frame 29 is alsoshown. A pair of commercially available solenoid operated air cylinders30 are attached to the frame 29 and are disposed alongside each of theconveyors 26. Each cylinder includes a plunger 31 guided by bracket 32to engage the upper indexing portion 33 which is aflixed to the starwheel 34. The solenoid operated air cylinders 30 are responsive to limitswitches 24 and sensors 24a. They are linked by conventional electriccircuitry which is not shown here. Star wheel 34, with the indexingportion 33 securely attached thereon, is rotatably mounted on uprightshaft 35 and rotates freely. The star wheel and indexing members arecontsructed from steel and are cut to fit the unit being packaged. Whensensors 24a do not contact a carton, plungers 31 are actuated andindexing members 23 stop the star wheels from turning, preventing cansfrom entering the machine. It should be noted that the can indexingassembly provides for stopping in groups of six cans, thereby obviatingthe need for the operator to manually remove the corresponding cans eachtime a missing carton occurs. When a carton is next contacted by sensors24a the solenoid operated plungers 31 are withdrawn and properly indexedcans proceed in timed relation with the carton blanks.

A chain and sprocket assembly 36 and 37, respectively, is secured to theframe and, as the cans proceed from the can indexing assembly, the cansare engaged by can engaging elements 38 which project outwardly from thechain 37. Can engaging elements 38 are spaced a predetermined distanceapart to carry cans to the wrapping station timed to coincide with thearrival of a corresponding carton blank at the wrapping Station,Conventional drive means are provided for sprockets 37 and the detail isnot shown here.

FIG. 4 shows carton blank 18 flowing through the machine in thedirection of the arrow and engaging sensors 24a which are attached tolimit switches 24. Limit switches 24 are securely mounted on the frameof the machine and may be adjusted to properly time the release of cansat the can indexing assembly with the arrival of carton 18 at thewrapping station of the machine. Structural framework of the machine isindicated in FIG. 4, by numeral 39. Limit switches 24 are commerciallyavailable and wired in parallel. The sensors 24a are simply rigid wiresattached to the limit switches in switch actuating relation. The sensorsare spaced so that at least one touches a carton blank at all times thatthe blanks are being properly discharged. When a blank fails todischarge both the sensors must fail to contact a carton blank beforethe plungers 31 are actuated, preventing the flow of cans until the nextcarton blank is sensed.

FIG. 6 shows the manner in which a carton blank is dispensed. Suctioncups 19 are advanced to the position shown in the dotted lines to grip acarton blank 18. Suction is applied and the suction cups are thenretracted to the position shown in the solid lines, gripping carton 18and placing the carton lblank leading edge adjacent the knurled roll 40.The suction is then released. This allows the knurled roll, which mateswith conveyor 22, to grip the blank. Conveyor 22 is driven by sprocket41 which rotates about shaft 42. Shaft 42 provides the pivot point ofthe reciprocating knurled roll 40 which advances the carton to theposition shown in the dotted lines and indicated at 40a. The blank isthen carried by conveyor 22 to conveyor 23 which includes pushers -23aspaced at a predetermined distance to carry carton blanks to thewrapping station coinciding with the arrival of a predetermined numberof cans to be wrapped. The drive means for the reciprocating suctioncups 19, as well as the means controlling the suction cycle andproviding the reciprocating action to roller 40 may be done in themanner disclosed by the above mentioned patent and is not shown here.

Referring to FIG. 2, the mechanism which provides for coordinating theknurled roll and suction cups at start-up or shutdown is shown indetail. Shaft 42 is show-n with a cam 43 mounted thereon above the shaft42. The cam 43 is elevated by rigid support 44 which gives cam 43 areciprocating motion substantially the same as the reciprocating motionof the knurled roll 40 shown in FIG. 6. Cam follower 45 rests on cam 43and actuates limit switch 46 in response to the motion of the cam 43.When cam 43 is forward, as indicated by the solid lines, limit switch 46is open and energizes pneumatic valve 20. In the position shown in thedotted lines, limit switch 46 is closed thereby shutting off the vacuumto suction cups 19. The limit switch is mounted on the hopper 16 bybracket 47 and is connected to pneumatic valve 20 with conventionalelectric circuitry, controlling the pneumatic valve in response to thecan supply in the pro duction line without the need for shutting downany part of the machine in a can shortage, but rather simply control thevacuum responsive to the can supply. Further, the cam 43 actuates thepneumatic valve 20 at the same point each time start-up or shutdownoccurs, providing automatic synchronization 'between the pneumatic valvewhich supplies the suction to the suction cups and the knurled roll 40which takes the cartons 18 away and places them on conveyor 22.

The cam and cam follower are constantly in motion as the machine isrunning. Limit switch 46 is connected to a sensing means in theproduction line with a time delay relay and locking circuit interposedin the circuitry. The relay (not shown) is locked into the circuit inthe on position and is maintained in the circuit until such time as acan shortage is sensed. At this point limit switch 46 is closed when cam43 is rearwardly and acted upon cam follower 45. This shuts oif thepneumatic valve and suction to suciton cups 19 is no longer provided.However, the suction cups maintain their reciprocating motion but -donot draw cartons for conveying to the wrapping station. When theproduction line sensing means senses cans the time delay relay isenergized and, upon timing out opens limit switch 46 when the cam 43 isforward and locking it in the circuit thereby opening valve 20 andsupplying suction to the reciprocating suction cups 19 at thepredetermined point in their reciprocating movement. This cycle ofoperation occurs each time cans are not sensed in the Production lineand provides automation with respect to dispensing the cartons inresponse to the can production line.

FIG. 7 shows the production line can sensing means which includes a canpressure gate assembly 48 and auxiliary can sensing assembly 49 whichtogether7 through conventional electric circuit-ry, control limit switch46 which in turn is controlled by cam and cam follower 43 and 45respectively. The time delay relay and locking circuit is interposedbetween the production line can sensing means and the limit switch 46.The direction of can flow is in the direction indicated by the arrow inFIG. 7.

FIG. 5 shows a plan view of the pressure gate assembly 48 and the cansensing assembly 49 with can flow as indicated. The pressure gateassembly 48 comprises a spring loaded, hinged gate portion 50 in theguide rail 51 of the production line, which production line cornprises apair of guide rails 51 and 51a. The gate is hinged by hinge 52 and isspring loaded, utilizing spring 53 which is mounted on post 53a whichprojects outwardly from the stationary rail 51. Bracket 54 is attachedto the gate portion 50 and includes an aperture (not shown) allowingpost 53a to be inserted in the aperture. Spring 53 maintains gateportion 56 in a normally continuous relation with stationary guide rail51. This position is indicated by the dotted lines and is maintainedwhen there is not can ow through the gate. Guide rail 51a is widenedopposite gate portion 50 to supply added pressure to the gate portion.The widened portion is indicated at 51b. A limit switch 55 is mounted onbracket 55a which in turn is mounted on the supporting framework of theproduction line. Limit switch 55 is actuated in response to a cam SSbwhich r-olls on gate portion 50 as the gate p0rtion is moved to the openposition thereby actuating the limit switch 55, as can ow continues alocking circuit maintains limit switch 55 in the circuit.

The auxiliary can sensing assembly 49 includes a limit switch 56 andsensor 57 attached in actuating relation to the limit switch 56. Limitswitch 56 is placed in conventional series circuit with switch 55,sensing can ow. When can flow is no longer sensed by sensor 57, limlLswitch 56 is closed, dropping out the locking circuitry, which in turnactuates limit switch 55. At this point, since cans are no longer sensedby the gate assembly and auxiliary sensing assembly, the time delayinterposed between the production line and the dispensing assembly isenergized and subsequently provides for interruption in the flow ofcartons without stopping the machine, until such time as the can supplyis replenished.

The time delay relay interposed between the production line and thecarton blank dispensing mechanism is commerically available and is notshown here. The time delay is timed dependant upon the length of theproduction line, particularly the length between the production line cansensing mechanism and the overall length of the production line. Otherfactors may be considered in determining the time delay necessary.

A emergency sensing mechanism may be provided on the discharge end ofthe packaging machine. Sensing means may be interposed in the outgoingproduction line of packaged goods to prevent the packaged goods frombacking up into the machine at such times as a master packing operationmay not be able to keep up with the production of the packaging machine.This may be done in any of several ways, none of which are shown here. Acommon method comprises installing a limit switch with a sensing leverattached thereto in actuating relation, interposed in the outgoingproduction line. At such times as the sensing lever senses interruptionin the flow of packaged goods, the machine is automatically shutdownuntil such time as ow is resumed. All stations of the machine should beshutdown in this instance to prevent damage to the various working partsof the machine.

Operation \Operation of the machine is begun by actuating the start-stopbutton 10b. The operator pushes the start button and cylinders 30 areactuated through conventional solenoids forcing plungers 31 outwardly tocontact indexing portion 33 thereby retarding the flow of cans to themachine 10. Since the cans are prevented from flowing into the machine,they build up along the conveyor production line 11 to auxiliary ca nsensing assembly 49 and then to pressure gate assembly 48. This actuateslimit switches 55 and 56, which are in series, and which are linkedthrough conventional electric circuitry to limit switch 46. Limitswitches 55 and 56 provide against short periods of sufficient flow ofcans through gate assembly 48 and sensor 49 from starting the flow ofcartons at the carton dispensing assembly 15 in that both switches mustbe affected. A commercially available time delay relay is interposed inthe circuit between limit switches 55/56 and 46. The time delay is timeddependant upon such variables as the length of the production line orthe distance from the gate to the end of the can conveyor. When the timedelay times out, after build-up past the gate has occurred, the relay isenergized allowing cam and cam follower 43 and 45 respectively to openlimit switch 46. Cam 43 causes the limit switch 46 to be opened whensuction cups 19 are at a predetermined position. When the limit switch46 is opened pneumatic valve 20 is actuated supplying suction to suctioncups 19. At this point a conventional locking circuit is actuatedmaintaining limit switch 46 in the circuit. This allows the suctioncycle to continue normally even though the cam and follower continuetheir reciprocating movement. The suction to the cups is alternated towithdraw and subsequently release carton blanks as disclosed in theabove mentioned Ganz patent.

When a shortage of cans is sensed and limit switch 56 is not satisfied,cam and cam follower 43 and 45, respectively close limit switch 46 atthe predetermined position. The circuit may also be set so that switches55 and 56 must be satisfied before switch 46 is closed. This willprevent short can flow interruptions from stopping the cartons. Thisshuts off the vacuum without shutting olf any of the other parts of themachine. Since the vacuum is off, cartons are no longer dispensed untilsuch time as sufficient can supply is again built up. This satisfiesswitches 55 and 56 and can ow resumes as described above. This cycle isrepeated each time a shortage and subsequent replenishment occurs, thecontinuous operation of the machine being maintained at all times.

In the instance of a carton blank shortage or skipped carton due toexcess moisture or similar malfunctions, the sensors 24a do not contacta carton blank and subsequently actuate the solenoid operated aircylinders 30. Plur'gers 31 engage the indexing portion 33 interruptingthe ilow of cans into the machine. After predetermined groups of sixcans have proceeded into the machine sui cient to meet the last cartonwhich was sensed by sensors 24a, lflow of cans ceases until carton owbegins. While the ow of carton blanks is interrupted the balance of themachine continues operation and the drive motor need not be shut-off.When the carton blank shortage is corrected, the cartons ow as above andare sensed by sensors 24a. The solenoid is actuated and plungers 31retract allowing cans to proceed in groups of six. The sensors 24a maybe spaced apart to prevent short interruptions in carton ow fromstopping can ow. Each time a carton shortage occurs the above operationautomatically repeats without the need of any assistance of an operatorand without aiecting any other of the working parts of the machine.

After initial start-up the machine continues running without the needfor any supervision except with respect to machine jams. If there are nocans, no cartons are dispensed; if there are no cartons, no cans aredispensed. When shutting down the machine at the end of the day, cartonoverride 10c is actuated which holds limit switch 46 in the circuitallowing cartons to be dispensed even though limit switches 55 and 56 inthe production line have been actuated since no cans are present.

A sensing assembly may be included at the discharge end of the packagingmachine to sense iiow of packaged units. If flow ceases and units aresensed, the machine should be shut down to prevent the packaged goodsfrom backing up into the machine. The machine should start automaticallywhen discharge ilow resumes.

It will, of course, be understood that various changes may be made inthe form, details, arrangement and proportions of the various partswithout departing from the scope of our invention.

What is claimed is:

1. A packing machine adapted to wrap cans and the like into packages ofa predetermined number of cans, said packaging machine comprising,

a wrapping station,

a carton blank dispensing mechanism adapted to continuously dispense aplurality of carton blanks in single tile order,

a carton blank conveying system adapted to continuously convey cartonblanks to said wrapping station whereby the carton blanks arrive at saidwrapping station corresponding to the arrival of cans,

a can conveying system adapted to continuously move a plurality of cansto said wrapping station in groups of a predetermined number wherebyeach group arrives at said wrapping station simultaneously with thearrival of a corresponding carton blank,

can sensing means interposed in said can conveying system, said cansensing means including a sensor adapted to project into the stream ofcontinuously moving cans on said can conveying system,

a sensor limit switch connected to said sensor in actuating relation,whereby said limit switch is actuated in response to flow of cans incontact with said sensor,

said can sensing means also including a pressure gate interposed in saidcan conveying system, said pressure gate adapted to respond to the flowof a continuously moving stream of cans,

a pressure gate limit switch connected to said pressure gate inactuating relation, whereby said limit switch is actuated in response toilow of cans through said pressure gate,

circuit means connecting said pressure gate limit switch to said sensorlimit switch whereby only the flow of cans for greater than apredetermined duration actuates said pressure gate limit switch and saidsensor limit switch, and

circuit means connecting said pressure gate limit switch and said sensorlimit switch to said carton blank dispensing mechanism, said cartonblank dispensing mechanism responsive to said sensor limi-t switch andsaid pressure gate limit switch whereby a can shortage interrupts saidcarton blank dispensing mechanism interrupting carton blank flowcorresponding to the period of can shortage.

2. The packaging machine of claim 1 including carton blank sensing meanscomprising,

at least one sensor adapted to project into the stream of continuouslymoving carton blanks on said carton bla-nk conveying system,

at least one sensor limit switch connected to said sensor in actuatingrelation whereby said limit switch is actuated in response to the ow ofcarton blanks in contact with said sensor, and

circuit means connecting said limit switch to said can conveying system,said conveying system responsive to said sensor whereby a carton blankshortage interrupts said can conveying system interrupting can flowcorresponding to the period of carton blank shortage.

3. A packaging machine adapted to wrap cans and the like into packagesof a predetermined number ot' cans, said packaging machine comprising,

a wrapping station,

a carton blank dispensing mechanism adapted to continuously dispense aplurality of carton blanks in single le order,

a carton blank conveying system adapted to continuously convey cartonblanks to said wrapping station whereby the carton blanks arrive at saidwrapping station corresponding to the arrival of cans,

a can conveying system adapted to continuously move a plurality of cansto said wrapping station in groups of a predetermined number wherebyeach group arrives at said wrapping station simultaneously with thearrival of a corresponding carton blank,

carton blank sensing means interposed in said carton blank conveyingsystem and including a pair of sensors adapted to project into thestream of continuously moving carton blanks on said carton blankconveying system, said pair of sensors spaced apart to permit one ofsaid sensors to contact the leading edge of a carton blank and the otherof said sensors to contact the trailing edge of a carton blank,

a pair of sensor limit switches connected to said sensors in actuatingrelation, whereby said limit switches are actuated in response to theiiow of carton blanks in contact with said sensors,

circuit means connecting said sensor limit switches to said canconveying system, said can conveying system responsive to said sensorswhereby a carton blank shortage interrupts said can conveying systeminterrupting can flow corresponding to the period of carton blankshortage, and

circuit means connecting said pair of sensor limit switches whereby onlyinterruptions in the flow of carton blanks greater than a predeterminedduration actuate said can conveying system.

4. The packaging machine of claim 3 including can sensing means whichcomprises,

a pressure gate interposed in said can conveying system, said pressuregate adapted to respond to the flow of a continuously moving stream ofcans,

a pressure gate limit switch connected to said pressure gate inactuating relation, whereby said limit switch is actuated in response tohow of cans through said pressure gate,

circuit means connecting said pressure gate limit switch to said sensorlimit switch whereby only the flow of cans for greater than apredetermined duration actuates said pressure gate limit switch and saidsensor switch, and

circuit means connecting said pressure gate limit switch and said sensorlimit switch to said carton blank dispensing mechanism, said cartonblank dispensing mechanism responsive to said sensor limit switch andsaid pressure gate limit switch whereby a can shortage interrupts saidcarton blank dispensing mechanism interrupting carton blank flowcorresponding to the period of can shortage.

5. An attachment adapted to substantially automate a packaging machinehaving a wrapping station, a can conveying system, a carton blankdispensing mechanism responsive to the can conveying system and a cartonblank conveying system, said attachment comprising,

can sensing means adapted to be interposed in the can conveying system,the carton blank dispensing mechanism being responsive to said cansensing means, said can sensing means including,

a pressure gate adapted to be interposed in the can conveying system,said pressure gate responsive to the flow of a continuously movingstream of cans,

a pressure gate limit switch connected to said pressure gate inactuating relation, whereby said limit switch is actuated in response toow of cans through said pressure gate,

a sensor adapted to project into the stream of continuously moving canson the can conveying system,

a sensor limit switch connected to said sensor in actuating relation,whereby said sensor limit switch is actuated in response to flow of cansin contact with said sensor,

circuit means connecting said pressure gate limit switch to said sensorlimit switch whereby only interruptions in the flow of cans greater thana predetermined duration actuate said pressure gate limit switch andsaid sensor limit switch, and

circuit means connecting said pressure gate limit switch and said sensorlimit switch to the carton blank dispensing mechanism, the carton blankdispensing mechanism responsive to said sensor limit switch and saidpressure gate limit switch whereby a can shortage interrupts said cartonblank dispensing mechanism interrupting carton blank ow corresponding tothe duration of can shortage.

6, An attachment adapted to substantially automate a packaging machinehaving a wrapping station, a carton blank dispensing mechanism, a cartonblank conveying system and a can conveying system responsive to thecarton blank conveying system, said attachment comprising,

carton blank sensing means adapted to be interposed in the carton blankconveying system, the can conveying system being responsive to saidcarton blank sensing means, said carton blank sensing means including,

a pair of sensors adapted to project into the stream of continuouslymoving carton blanks on the carton blank conveying system, said pair ofsensors adapted to be spaced apart to permit one of said sensors toContact the leading edge of a carton blank and the other of said sensorsto contact the trailing edge of a carton blank,

a pair of sensor limit switches connected to said sensors in actuatingrelation, whereby said limit switches are actuated in response to theflow of carton blanks in contact with said sensors,

circuit means connecting said sensor limit switches t0 the can conveyingsystem, the can conveying system responsive to said sensors whereby acarton =blank shortage interrupts said can conveying system interruptingcan ow correspond-ing to the period of carton blank shortage, and

circuit means connecting said sensor limit switches whereby onlyinterruptions in the ow of carton blanks greater than a predeterminedduration actuate said can conveying system.

7. The attachment of claim 5, said attachment further including,

carton blank sensing means adapted to be interposed in the carton blankconveying system, the can conveying system being responsive to saidcarton blank sensing means, said carton blank sensing means including,

a pair of sensors adapted to project into the stream of continuouslymoving carton blanks on the carton blank conveying system, said pair ofsensors adapted to be spaced apart to permit one of said sensors tocontact the leading edge of a carton blank and the other of said sensorsto contact the trailing edge of a carton blank,

a pair of sensor limit switches connected to said sensors in actuatingrelation, whereby said limit switches are actuated in response to the owof carton blanks in contact with said sensors,

circuit means connecting said sensor limit switches to the can conveyingsystem, the can conveying system responsive to said sensors whereby acarton blank shortage interrupts said can conveying system interruptingcan ow corresponding to the period of carton blank shortage, and

circuit means connecting said sensor limit switches whereby onlyinterruptions in the flow of carton blanks greater than a predeterminedduration actuate said can conveying system.

References Cited UNITED STATES PATENTS 2,751,730 6/1956 Gentry 53-55 X2,860,461 11/1958 Arneson 53-63 X 2,919,526 1/1960 Arenson 53-593,253,385 5/1966 Beermann et al. 53-55 3,262,242 7/ 1966 Godschalx 53-5545 TRAVIS S. MCGEHEE, Primary Examiner.

R. L. SPRUILL, Assistant Examiner.

U.S. Cl. X.R.

